Process and device for preventing malfunction of a dental evacuation system

ABSTRACT

To prevent, as far as possible, malfunction of a dental evacuation system, portions of a free-flowing additive are added at intervals to at least one constituent of the liquid-solids mixture. This is repeated several times during each period of operation of the evacuation system within the first evacuation section, which includes the separator (1). The additive added in portions may be, for example, a disinfectant, a cleaning agent and/or an anti-foam agent.

The invention concerns a process and a device for preventing functionalbreakdowns in a dental suction unit, in which a mixture of a liquid andsolid matter is suctioned out of the patient's mouth using a vacuum andgoes through an initial suction line that ends at a trap, where the airis separated out and goes to the vacuum pump. The trap also preferablyseparates the liquid from the solid matter, which is caught in aremovable collection container, and the liquid is drained off.

BACKGROUND OF THE INVENTION

Dental suction units, as described for example in WO-A-86/03669, areplagued with special problems because of the composition of the mixtureto be suctioned and treated (blood, saliva, water, pus, tooth material,residues of amalgam, etc.), which can lead to serious functionalbreakdowns. These problems come from cleaning and disinfecting the partof the system through which the mixture flows, which is hereafter calledthe initial suction line, and also from the fact that blood mixing withthe hydrogen peroxide constantly used in dentistry can cause anintensive build-up of foam, which shuts down the system, since theoutlet to the vacuum from the trap must naturally be safeguarded againstforeign matter flowing through it. The foam that is created has aparticularly great stability, and dissolving it automatically takesseveral hours. On the other hand, dissolving, cleaning and sterilizing atrap is not only time-consuming, but is also an unhygienic activity,since the mixture has a very high concentration of bacteria.

We know how to simplify at least the cleaning or disinfection fromEP-B-23036. In it, the outflow duct for the trapped, unseparated mixtureof liquids and solid matter has a siphon that siphons off a cleaner froma cleaner container with a rinsing duct at the end whose other end canbe connected to a suction hose. The unit can be cleaned or disinfectedat the end of a working period, usually at the end of the daily officehours, by connecting the suction hose to the rinsing duct and hooking upthe suction unit so that the additive to be added then flows through theinitial suction line.

While work is going on, it is hardly possible to add the additive sincethe equipment makes it impossible for the dentist to work in theinterim. According to EP-A-237708, on the other hand, the trap, whichhas an extraction pump for the trapped liquid and preferably also acentrifuge, is fitted with a propeller, which is between the air trapand the liquid collection space. The foam that builds up is supposed tobe destroyed using the propeller. This may work satisfactorily when thepump is running, but when the pump is turned off, the propeller does notprevent the undisturbed, built-up foam from passing through. (The foambuild-up takes place gradually, even when the unit is temporarilystopped.) On the other hand, the foam that has gotten into the air trapprevents the suction unit from being turned on, which causes thebreakdown mentioned at the beginning. Adding a cleaner or disinfectantis not described in that publication.

SUMMARY OF THE INVENTION

The invention is based then on the idea that the prevention of foambuild-up or at least its fast, direct destruction would practically ruleout functional breakdowns caused by foam, and that more frequentcleaning and disinfection would also prevent at least those functionalbreakdowns that result from excess accumulation of contaminants.

The task of the invention is therefore to create a process and a deviceto prevent such functional breakdowns, in order, if possible, to extendthe maintenance intervals so that the corresponding maintenance workwill be needed when the whole unit is serviced or when the collectioncontainer is emptied, etc.

The invention does this by adding a free-flowing additive to at leastone component of the mixture within the initial suction line atintervals during each period that the suction unit is operating.

Free-flowing additives are understood to be any agents suitable foreliminating at least one of the problems listed. Thus, a disinfectantand/or a cleaner and/or an anti-foaming agent can be added in portions.Such additives, and anti-foaming agents as well, are known as such andare available on the market, so that there is no need to go into greaterdetail about them.

The concept of preventing the creation of foam or destroying it with anadded anti-foaming agent is therefore unique to the invention.

Thus the additive will preferably consist of a mixture of all agentsthat can be used or are needed, which also expands the range of usablecleaners or disinfectants from which to choose, since high-foamingagents can also he used because the foam build-up is eliminated anywayby an anti-foaming agent.

The additive or mixture of additives is added within the initial suctionline defined above, which begins at the mouthpiece. In a new suctionunit, it can be added there, preferably; if a system that already has acleaning system according to EP-B-23036 mentioned above is beingrefitted or expanded, the process in the invention can be limited to theaddition of an anti-foaming agent. This, then, preferably takes place atthe end of the first suction line, in the trap itself. If the solidmatter is sedimented in the collection container, it is preferable toprovide for the anti-foaming agent to be added in portions to the liquidcollecting above the sedimented solid matter.

The additive can be added at regular intervals during the operatingperiod, for example, every quarter of an hour around the clock. In onepreferred version, however, the additive is preferably added upon eachtransition from a working phase to a resting phase. Such transitionstake place frequently enough during the operating period, approximatelyone hundred to two hundred times during a full day of office hours.Since the anti-foaming agents in particular are still effective whenhighly diluted, when this process is being carried out, the portion ofthe additive that is being added can be limited to a few drops, so thatthere is no excessive use.

In one preferred version, it is added during the resting phase and isreleased when the pressure in the suction unit drops, or each time themouthpiece is hung up.

A device for carrying out the process in the invention includes,according to the invention, a container to hold a supply of theadditive, a line coming out of the container that has a dosage device onit, and an interval-control device for adding a portion from the supplyeach time.

The intervals can be controlled by a control unit, wherein the intervalsmay be equal or unequal. But this requires additional expense for parts,if the control is electrical or electronic.

Control is simplified by the fact that the dosage device has a valveunit controlled by the vacuum pressure, since the control impulsesrequired are given by the frequent switching.

One preferred version of a valve unit consists, for example, of the factthat it includes two return valves and a dosage pump arranged betweenthem that can operate either electrically or by changes in pressure. Oneinexpensive design for the return valves provides that they be in theform of flap valves, at least one of which is weighted to return. Thisflap valve then opens upwardly, and the valve flap touches thesupporting body, especially a support ball. A reciprocating pump,wherein a diaphragm pump is preferably used that does not need its ownpiston seal, is especially suitable for the dosage pump.

Thus the diaphragm can be made to move advantageously by the negativepressure in the suction unit, and the return movement can be broughtabout by a return spring or by gravitational force.

Another version of the device provides for the container to be arrangedabove the dosage device, which has a stop valve in the duct, wherein theadditive flows out of the container under the influence of gravity. Amagnetic valve or, preferably a valve controlled by negative pressure,can be used as the stop valve.

The suction action of a suction unit is generally very high, and anoperating pressure of 0.1 bar can easily be reached. It is thereforeinsignificant if slight quantities of outside air get into the suctionline. For this reason, preferably, there is an design in which theoutlet of the dosage device is arranged under a filling funnel that isunder atmospheric pressure, whose spout empties into thenegative-pressure system within the initial suction line. Since theamount of the dose is only a few drops, the cross section of the spoutcan be kept very small, but the capillary forces, which could preventthe outflow under the force of gravity, cannot cause breakdowns, sinceeach time the suction unit is turned on, the portion of additive thatremains in the filling funnel or in this spout is sucked into theinitial suction line.

Another version provides for the conduit from the container to beairtight and to empty into the negative-pressure system of the suctionunit within the initial suction line, and for it to have a stop valve asthe dosage device. According to this design, the portions released bythe stop valve, activated electrically or by negative pressure, aresucked directly out of the container. In the designs described untilnow, the additive is under normal air pressure in the container. But itis also possible to integrate the container into the negative-pressuresystem of the suction unit and to equip it with a lift-type stand pipe,wherein the pressure difference specified by the angle of the stand pipeis sufficient to dispense the portion to be dispensed from the supply.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail below, using theFigures in the enclosed drawings, but it is not limited to them.

FIG. 1 shows a schematic representation of a preferred version of theinvention;

FIG. 2 a vertical section through one example of a version with a dosagedevice arranged on the trap;

FIG. 3 an overview of the design in Fig 2;

FIG. 4 a section along the line IV--IV in FIG. 5;

FIG. 5 a section along the line V--V in FIG. 3;

FIG. 6 a section similar to FIG. 5, through another design of a dosagedevice; and

FIGS. 7 and 8 schematic representations of two other versions of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A dental suction unit has, according to FIG. 1, a vacuum pump 5, whosevacuum duct starts at a mouthpiece 3 of a manual suction device. Thesuction duct leading to the pump 5 has an initial section 2 between themouthpiece 3 and the trap 1. In the trap 1, there is a separation of themixture of liquid and solid matter vacuumed through the mouthpiece 3,wherein the separated vacuum goes to the pump 5 via a second section 4of the suction duct, the liquid leaves the trap 1 via the outflow duct7, and the solid matter is collected in a removable collection container6, in which it is preferably sedimented. A container 8 is used forholding a cleaning and/or disinfecting and/or foam-destroying additive,and has a conduit 9 in which a dosage device 10 is contained, by meansof which the additive is conveyed in portions of a few drops into aninitial suction line of the system. This initial suction line includesthe part of the suction unit that the mixture flows through, i.e., itincludes the mouthpiece 3 and the trap 1. The additive can also beinserted at another site on the initial suction line, as shown by thebroken line 9'.

The trap shown in FIG. 2 has an air-collection chamber 40 on the inputside of the initial section 2 of the suction line, from which the cleansuctioned air goes via part of the trap 1, not shown in detail, to theconnection for the section 4 of the suction line. Within the chamber 40,there is a motor 41, which has a pump 42, from which the outflow line 7goes to carry off the separated liquid. Assigned to the pump 42 is avacuum pipe 43 projecting into the removable collection container 6, andthere are filling-status sensors 38 that end at the height of the pump42 and switch the pump 42 on and off. A third filling-status sensor 37ends somewhere over the pump 42 and turns off the suction unit if thislevel is exceeded and prevents liquid from going to the second section4. The sensor 37 also reacts naturally to the foam created in theliquid-collection space 39.

The dosage device 10 for the additive coming through the duct 9 isplaced in a cover 13 of the trap 1.

As can be seen from the details in FIGS. 3 to 5, the dosage device 10has a frame 14, which has a valve 15 with an inlet 16 and an outlet 17.The valve 15 and the frame 14 hold in place a diaphragm 18 that has twovalve flaps 19, 20, which lock or release the openings 21, 22 in thebasic frame 14. The valve flap 19 locks the inlet 16 and opens belowinto a dosage space 23, which is surrounded by a pump diaphragm 24 ofthe dosage pump, The pump diaphragm 24 is stretched between the frame 14and a counterpart 44 and is thus inside the trap 1, wherein screws, notshown, attach the valve 15, the frame 14 and the counterpart 44 to oneanother. A moveable piston 25 admitting the pump diaphragm 24 from theoutside is located in the counterpart 44 and has an opening 27 with areturn spring 26.

The valve flap 20, as part of the outlet valve opens upward into anoutlet space 28, in which a ball 29 is arranged as a loading weight ofthe valve flap 20. The outlet 17 of the dosage device 10 goes into afilling funnel 11 open to the atmosphere, which is arranged in the frame14, and to which an outflow pipe 30 is connected which projects into theliquid collection space 39.

The apportioning of the pre-supplied additive in the container 8 nowtakes place under the influence of the pressure changes in the suctionunit as follows: When the suction unit is turned off, the pump diaphragm24 presses on the lower side of the frame 14 via the return spring 26,and the additive in the duct 9 is thereby prevented from flowing throughby the dosage device 10. When the suction unit is turned on, it ispulled down against the return spring 26 by the negative pressureoutside on the pump diaphragm 24, whereupon the additive in the dosagespace 23 flows through the open valve flap 19. The valve flap 20 isclosed and the weight of the ball 29 puts pressure on it. A small,harmless quantity of outside air goes into the trap 1 through thefilling funnel 11.

As soon as the suction unit is turned off in its cabinet by hanging upthe mouthpiece 3, the piston 25 moves up via the return spring 26 andpresses the pump diaphragm 24 on the lower part of the frame 14. Thevalve flap 19 closes and the valve flap 20 opens, removing the ball 29.The portion of additive, which consists of a few drops, (the picture inFIGS. 4 and 5 corresponds to double the natural size) goes via theoutlet 17 into the filling funnel 11, from which the liquid in theliquid collection space 39 is added via the outflow pipe 30. If theadditive is an anti-foaming agent, the foam build-up is prevented andany foam created is destroyed. If the additive is a disinfectant, germscontained in the separated liquid will be rendered harmless.

When the unit is turned on again, any remaining residues of the portionjust fed in are suctioned off via the suction effect from the openfilling funnel 11, so that the portion is completely added by acapillary action of the outflow pipe 30. The pump diaphragm 24 ispressed down by the negative pressure under compression of the returnspring 26, so that the dosage space 23 is enlarged, whereby the nextportion flows out of the container 8 via the valve flap 19 that isopening. The closed valve flap 29 pressed down by the ball 29 preventsthe aspiration of outside air via the outlet 17. In this way, each timethe suction unit is turned off, i.e., at the beginning of a restingphase, a portion of the additive goes into the inside of the trap.

The design shown in FIG. 6 of the dosage device 10 works in the oppositeway, i.e, the dosaged portion goes into the trap 1 each time the suctionunit is turned on, that is, at the beginning of the work phase. In thisdesign, return valves 31, 32 with ball-shaped valves 33 and returnsprings 34 are provided as valves, and the dosage space 23 is borderedby pistons 25 sealed directly into the frame 14, to which the returnspring 26 is in turn assigned. The dosage device, according to FIG. 6,is also suitable for building into the cover 13 of the trap, but canalso be mounted in another place as a closed part. In this design, theapplication of negative pressure to the opening 27 in an otherwiseclosed suction space 26 lifts a diaphragm 35 to which the piston 29 isattached and when the negative pressure is lifted, it is moved back tothe place shown by the spring 26 or by its own weight. The dosage of theadditive takes place, depending on the design, according to FIGS. 3 to5.

As just mentioned, using a change in pressure to activate the dosagedevice has a special advantage, since additional control devices areunnecessary. However, the dosage device could also be activated by amagnetic valve or even mechanically, and in these designs, otherintervals could be used as the switching intervals of the suction unit.Thus, portions could also be added at regular intervals by using a clockrelay. An example of such a design is shown schematically in FIG. 7.Here, the container 8 is placed above the trap 1, so that the additivecan flow into the filling funnel 11 via the duct 9 by the force ofgravity, as soon as a stop valve 12 of any kind is opened and closedagain, depending on the time or the amount of flow, as in counting thedrops. In this version, it can be added at any time desired.

Another design that also doses by means of negative pressure is shown inFIG. 8, wherein here the additive is aspirated out of the containerlying under the trap 1 by the negative pressure, as soon as the stopvalve 12, which is in turn controlled by the time or the amount of flowthat the dosage device 10 forms, opens and closes. According to thisdesign, dosage can take place at any time during a work phase.

Coming back to FIG. 1, it is also possible to have the dosage devices,primarily of the designs described in FIGS. 6 to 8, empty at any placein the initial suction line, as shown by the broken line 9'. If thecontainer 8 also contains a cleaner and/or disinfectant as the additive,then it is an advantage to add it directly at the mouthpiece 3, wherebythe whole initial suction line coming into contact with the liquid andsolid matter can be cleaned, disinfected and provided with ananti-foaming agent.

We claim:
 1. A process for preventing functional breakdowns in a dentalsuction unit by preventing the build-up of foam in the suction unitduring dental treatment, comprising:a) inserting a suction nozzle of asuction line into a patient's mouth whereby said suction line has afirst and a second section, wherein said suction nozzle is in said firstsection, b) creating a negative pressure in said suction line throughthe attachment o said second section to a suction pump, c) aspiratingthe contents of a patient's mouth into said first section whereby saidcontents contain a mixture of solids and liquid material, d) routingsaid mixture from said first section to a separator dividing said firstand second sections of said suction line, whereby said separatorcomprises an air separating chamber and a mixture separating chamber, e)separating air from said mixture through said air separating chamber, f)collecting said mixture in said mixture separating chamber, g) adding atdefinite intervals to said mixture aspirated through said first sectionof said suction line, a free-flowing additive containing an anti-foamingagent, h) repeating steps a)-f) without risk of unit malfunction due tothe accumulation of substances in the unit.
 2. The process of claim 1,wherein said free-flowing additive of step g) contains a disinfectant.3. The process of claim 1, wherein said free-flowing additive of step g)contains a cleaning agent.
 4. The process of claim 1, wherein saidfree-flowing additive of step g) is added within said suction nozzle. 5.The process of claim 1, wherein said free-flowing additive of step g) isadded into the mixture collecting chamber of the separator.
 6. Theprocess of claim 1 wherein said free-flowing additive of step g) isadded at each transition between a working phase and a resting phase ofthe pump.
 7. The process of claim 1, wherein the addition of said freeflowing additive of step g) is triggered by cancellation of the negativepressure in the suction unit.
 8. A suction unit capable of continuingdental treatment without risk of unit malfunction due to the presence ofcertain substances, said unit comprising;a suction line having a firstsection and a second section, wherein said first section is adapted foruse in a patient's mouth, pump means connected to said second section ofsaid suction line for creating a negative pressure therein therebyeffecting aspiration of a mixture of solids and liquids from a patient'smouth into said suction line, separating means contained in said suctionline, for directly receiving an additive and said contents contained insaid suction line, whereby said mixture is collected and air isseparated out to return to said pump means, container means forcontaining a supply of an additive capable of counteracting theformation of substances causing unit malfunction, dosage means fordefining portions of said additive to be added to said first section forcombination with said mixture, said dosage means comprising a ductconnecting said container with said first section of said suction line,and a valve unit controlled by vacuum pressure, wherein said valve unitfurther comprises two return valves with a dosage pump therebetween,interval-control means for controlling said dosage means whereby saiddosage means is effected in intervals, such that the formation ofsubstances causing unit malfunction is prevented.
 9. The suction unit ofclaim 8, wherein said return valves are flap valves, whereby one of saidvalves is weighted.
 10. The suction unit of claim 8, wherein said dosagepump is a diaphragm pump.
 11. The suction unit of claim 8, wherein saidduct is airtight and said dosage means further comprises a stop valve.12. A suction unit capable of continuing dental treatment without riskof unit malfunction due to the presence of certain substances, said unitcomprising;a suction line having a first section and a second section,wherein said first section is adapted for use in a patient's mouth, pumpmeans connected to said second section of said suction line for creatinga negative pressure therein thereby effecting aspiration of a mixture ofsolids and liquids from a patient's mouth into said suction line,separating means contained in said suction line, for directly receivingan additive and said contents contained in said suction line, wherebysaid mixture is collected and air is separated out to return to saidpump means, container means for containing a supply of an additivecapable of counteracting the formation of substances causing unitmalfunction, dosage means for defining portions of said additive to beadded to said first section for combination with said mixture, saiddosage means comprising a duct having a stop-valve placed therein, saidduct connecting said container with said first section of said suctionline, wherein said container means is placed at a height above saiddosage means, such that said additive flowing from said container tosaid dosage means is gravity assisted, interval-control means forcontrolling said dosage means whereby said dosage means is effected inintervals, such that the formation of substances causing unitmalfunction is prevented.
 13. A suction unit capable of continuingdental treatment without risk of unit malfunction due to the presence ofcertain substances, said unit comprising;a suction line having a firstsection and a second section, wherein said first section is adapted foruse in a patient's mouth, pump means connected to said second section ofsaid suction line for creating a negative pressure therein therebyeffecting aspiration of a mixture of solids and liquids from a patient'smouth into said suction line, separating means contained in said suctionline, for directly receiving an additive and said contents contained insaid suction line, whereby said mixture is collected and air isseparated out to return to said pump means, container means forcontaining a supply of an additive capable of counteracting theformation of substances causing unit malfunction, dosage means fordefining portions of said additive to be added to said first section forcombination with said mixture, said dosage means comprising a ductconnecting said container with said first section of said suction line,and an outlet arranged in a filling funnel which is under atmosphericpressure, said funnel opening into said first section of said suctionline, interval-control means for controlling said dosage means wherebysaid dosage means is effected in intervals, such that the formation ofsubstances causing unit malfunction is prevented.
 14. A process forpreventing functional breakdowns in a dental suction unit by preventingaccumulation of substances causing unit malfunction during dentaltreatment, comprising:a) inserting a suction nozzle of a suction lineinto a patient's mouth whereby said suction line has a first and asecond section, wherein said suction nozzle is in said first section, b)creating a negative pressure in said suction line through the attachmentof said second section to a suction pump, c) aspirating the contents ofa patient's mouth into said first section whereby said contents containa mixture of solid and liquid material, d) routing said mixture fromsaid first section to a separator dividing said first and secondsections of said suction line, whereby said separator comprises an airseparating chamber and a mixture separating chamber, e) separating airfrom said mixture through said air separating chamber, f) collectingsaid mixture in said mixture separating chamber, g) adding at definiteintervals to said suction nozzle a free-flowing additive containing ananti-accumulating agent, h) repeating steps a)-f) without risk of unitmalfunction due to the accumulation of substances in the unit.